Think that's far-fetched, or that employers wouldn't really care about fandom activity? Well, I know someone in my other fandom, a fanfic writer, who had to
delete her LJ, her account on the fanfic archive and other evidence of her presence on the internet because she's job-hunting and all this stuff turned up in a search on her and did her damage.
That's awful, poor girl! Scary, thought, definitely. Some of the employers should learn to chill a bit and appreciate the fact that the people they're hiring have some degree of imagination and creativity. It's usually a plus to have, in just about any job I can think of...
When I was hired here, I know they checked out references to me on the web, because it came up in the interview. However, luckily this turned out to be a real advantage, that I did 3D images and that I had my own webpage and what not. Of course, this is a software company, so they do like people who happen to spend their off time doing computer-y stuff.
Personnally, if I ever went job hunting and found that an employer thought my online activities were questionnable (which, seriously, they really aren't!) then I don't think I'd be that bothered -- that is not a company I'd want to work for anyway. Too stiff and straight. I have a lot more fun here, where people think outside the box! You'd be surprised at the activities we organize here...
Check this YouTube vid, for instance -- these are all people I work with. The guy who *won* the competition is my *boss*. And half the guys there have read my stories, too, so... hey, life's good for now.